Hi Brian, just a quick note here:

> I used a new CPlane on each line segment, rotated the handle to place the red
> axis tangent to the curve, (= place an axis parallel to the line segment),
> then did a rotate axis. This was lots of repetition.

I haven't looked at the particular geometry here, but usually if you're going to use rotate axis you should not need to place the cplane at all beforehand. Rotate axis does not use any information about the current cplane to do the rotation, once you pick the 2 points for the rotation axis line that defines where it will rotate around.

That's basically why rotate axis exists, so that you can rotate something around some arbitrary line separately from needing to set the cplane to deal with it.

If you're picking rotation points with the mouse instead of typing in a value, you should see that your mouse automatically tracks on a plane normal to that rotation axis line, so there's sort of a temporary cplane used just within that command once the axis line is set.

- Michael